PandaFileKit

Convert WebM to MP4

Turn a WebM into an H.264 MP4 that plays on iPhones, in PowerPoint and in most editors.

WEBM → MP4

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Counted with the browser's Performance API during the last job. It sees every request the page makes, but not what is inside them, so anything that is not a static download is counted above.

To check yourself: open DevTools → Network, clear the list, run the tool, and inspect each request. None will contain your file. You can also switch to offline after the page loads; tools whose engine is already downloaded keep working.

Drop WebM file here

or paste, or choose a file

WEBM → MP4

Choose one video: MOV, WebM, MKV or M4V, up to 2 GB. It is read from your disk, never uploaded.

How to convert WebM to MP4

Drop the WebM and press Convert. WebM holds VP8, VP9 or AV1 video with Opus or Vorbis audio, none of which go into a standard MP4, so the video is always re-encoded to H.264 and the audio to AAC at 160 kbps. Expect the conversion to take roughly as long as decoding and encoding every frame on your device.

Step by step

  1. 01Drop the WebM file.
  2. 02Press Convert; the video is re-encoded to H.264 and the sound to AAC.
  3. 03Download the MP4.

Where WebM files come from

Many screen recorders, browser-based recording tools, video calls saved from the browser, and downloads from some websites produce WebM. It plays fine in Chrome and Firefox, but iPhones, PowerPoint, many video editors and some upload forms want MP4 with H.264.

Why it always re-encodes

Unlike MOV or MKV, a WebM never contains H.264, so there is nothing to copy. Re-encoding takes longer than a re-wrap and changes quality very slightly, but the result is the most compatible video format there is.

  • Screen recordings with lots of text stay sharp in H.264.
  • Long recordings take longer; trim first if you only need part.

Questions

Will WebM to MP4 lose quality?

Very slightly, because the video is re-encoded. For screen recordings and normal footage the difference is hard to see.

Why is my WebM slow to convert?

Every frame has to be decoded and encoded again. Speed depends on your device and the video's length and resolution.

Will the MP4 play on iPhone and in PowerPoint?

Yes. H.264 video with AAC audio in an MP4 is the format both support.

Is my recording uploaded?

No. The conversion runs in your browser with WebCodecs, so a recording of your screen stays on your device.

Same tool, other settings

All Video tools